Various paper handling systems are designed to process a wide variety of media items. These media items may be of various sizes and shapes and of various types of materials and documents. For example, if the media items are envelopes or other items such as third length slips, trifolds, or business return envelopes and small booklets, to accommodate and process a volume of items, the envelope may be shingled in a shingle feed tray. When these media items are moved from the shingle feed tray into the feeder mechanism, as the case may be, the items are separated from the other media in the tray for processing in the system. In this mode, the media items are stacked on edge in a feed tray and fed from the tray into the feeder.
To provide stack forces on the shingled media item, the angle of the feed tray with respect to a feeder has been varied, as has the weight of a moveable sled provided to urge the shingled media items toward the feeder. Feeders have utilized shingle feed trays mounted to the feeder with various tray angles such as between 22 and 25 degrees, to facilitate movement of the media items from the feed tray into the feeder. Arrangements of this type are employed in Pitney Bowes Inc. of Stamford, Conn., inserter products, such as the Pitney Bowes DI350, DI400, DI500, DI600, DI800 console inserter systems. At such angles, most shingled media items readily slide down the feed tray guided by the side guides of the tray. However, the stack force against the feeder nudger separator system to singulate shingled media items from the stack of media items in the feed tray becomes a strong function of the amount of shingled media items in the feed tray.
The reliable performance of the feeder in singulating the shingled media items becomes impacted by the amount of shingled media items in the feed tray pressing against the current media item to be singulated. Treatments have been added to the surface of the side guides of shingle feed trays to regulate the friction between the shingled media items and the side guides. These treatments are implemented in efforts to increase reliable movement of the shingled media item stack toward the exit area of the feed tray and the feeding and singulation of the media item at the feed tray exit area. Side Guide treatments have included tapes, Teflon paints, oils, and plastic shims. Side Guide treatments of this type have been employed in products such as the Pitney Bowes DI350, DI400, DI500, DI600, DI800 and console inserter systems.
The media in a shingle feed tray are usually stacked at an angle with the rear most media item resting against a sloped sled that advances as media items are moved from the shingle feed tray into the feeder of the paper handling equipment. Accordingly the media items are presented to the feeder in a trapezoidal form. The stack of shingled media items are in the shape of a trapezoidal solid. The media items are presented to the feeder with the weight of the trapezoid media items stack pressing against the nudger system.
Shingle feed problems have been encountered in moving media items from a shingled feed tray into a feeder due, in part, to distortions of the media items such as packaging, envelope “propeller”, etc. Envelope distortion due to propeller is induced when the paper used to construct envelopes reacts to the moisture content of the air. The orthotropic expansion response of paper to moisture results in a twist of the form of the envelope, which forms a saddle curve shape under the strain. In addition, poor packaging of envelopes can result in media distortion, as envelopes typically have non-uniform thicknesses that result in uneven pressures between envelopes when packed in boxes for transport. Additional problems are created when shingle media advances to the nudgers, as the friction at the base of the piece can cause the media to gradually “stand-up”, moving from a trapezoidal shape to a more rectangular shape. In the rectangular configuration, the incident angle between the tray and media increases, resulting in a greater propensity for the media to stub into the tray surface and skew.
The distortions noted above can create unbalanced forces on the media items, which may result in skew of the media items as they are moved from the shingle feed tray into the feeder. Various approaches to this problems have involved arrange feed nudger arrangements to control the orientation of the shingled stack. Such products have also employed highly polished side guides to eliminate potentially problematic stubs of the corners of material on the media side guides. Examples of such arrangements are employed in the Pitney Bowes DI350 and D500 and DI600 inserters. In these products, attention has been paid to the formation of the corner between the vertical and horizontal surfaces of the side guides. In addition, outboard support of the media is provided via external, outboard, nudgers (nudgers located toward the edges of the media) that act to support and induce even uniform bending of the media being fed. A high degree of complexity is introduced by the inclusion of the outboard nudgers, as to remain effective, the nudger location in such arrangements move inward and outward to follow the adjustment of the side guides.
The bending of the media items as they are moved into the feeder can further exacerbate the feeding problem of the shingled media items and result in jamming of the equipment as skewed items are bent and moved into the feeder mechanism. As media advances from the shingle tray to the separator, the media must be bent from a near vertical orientation in the shingle tray to a near horizontal orientation in the feed head. As bending forces can be significant, uneven contact of the media across the width of the tray results in a net moment about the center of gravity of the envelope, inducing a skewed orientation of the media.